CN105181080B - A kind of digitlization capacitive level probe based on TDC chip technology - Google Patents
A kind of digitlization capacitive level probe based on TDC chip technology Download PDFInfo
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- CN105181080B CN105181080B CN201510407579.8A CN201510407579A CN105181080B CN 105181080 B CN105181080 B CN 105181080B CN 201510407579 A CN201510407579 A CN 201510407579A CN 105181080 B CN105181080 B CN 105181080B
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Abstract
The invention discloses a kind of digitlization capacitive level probes based on TDC chip technology, it include: digital sensing unit, micro controller unit, communication or output unit and mechanical structured member, the digital sensing unit, micro controller unit and communication or output unit are set in mechanical structured member, the heretofore described digitlization capacitive level probe based on TDC chip technology, by the way that TDC measuring unit is connect with mathematical logic processor, by digitlization TDC application signal by the delay time of interior logic gate come high-precision time of measuring interval, the point-device signal of construction again of chip is set to pass through logic gate number by simple circuit structure and special circuit board wiring method, its full accuracy depends on the largest logical gate delay time of chip, method than traditional analog circuit measurement capacitor is differentiated Rate improves 1000 orders of magnitude or more, and anti-interference ability improves 10 times or more, thus the problems such as very good solution anti-intense radiation interference, to better meet the demand of client.
Description
Technical field
The present invention relates to a kind of level meter field, specifically a kind of digitlization capacitance object position based on TDC chip technology
Meter.
Background technique
The on-line monitoring and control to level height is realized in the measurement process of level, and can key be accurately examine
Survey current level height.In recent years, there are many novel material level detection methods, various level indicators also have developed rapidly.
Mainly there are three developing direction for level measurement instrument at present: non-cpntact measurement, level meter are intelligent and minimize, is integrated.
Simultaneously with the development of science and technology and transplanting of the newest fruits of other related fieldss in terms of level gauging, so that object
Position measuring instrument obtains wider application in some special occasions (such as high temperature, high pressure, high vacuum), measurement accuracy there has also been
It is further to improve.In the current preferred capacitive level probe of these application of special occasions, it has, and structure is simple, resolving power is high,
Reliable operation, dynamic response are fast, and raw in workers and peasants the advantages that can work under the mal-conditions such as high temperature, radiation and judder
The every field of production is centainly applied.But traditional capacitive level probe is all made of analog circuit, anti-stray capacitance improves
Precision, enhancing stability and anti-interference and to reduce cost be always the bottleneck that capacitive level probe is promoted on a large scale.
Research for this field of capacitive level probe, foreign starting is early, input is rich, develops more fast
Speed just achieves the achievement attracted attention in the seventies, and up to the present, external many companies all develop representative
A series of multiple functional, high degree of automations, measurement with high accuracy series and corresponding product.E+H, P+F, Siemens such as Germany
Deng being all proposed the practical capacitive level probe of several moneys.The level of economic development in China is relatively backward, various basic activities
Capital investment it is few, each related fields develops slowly so that measuring technique, measurement method quite fall behind, product automation degree
It is not high.Precision, reliability, function etc. have very big gap with external level gauging level.
The capacitive level probe of the above instrument producer development & production both domestic and external, no matter the more height of the degree of automation all do not have
Have and solves lower this several technical problems: first is that anti-intense radiation is interfered, second is that multi-parameter comprehensive compensates, third is that extra small range level
Precise measurement.Its basic reason is not get rid of the constraint of traditional capacitor method of sampling.Domestic and international existing capacitance object position
The measuring circuit of meter probably has these types:, direct current charge-discharge method；, ac capacitor bridge；, exchange locking phase amplifying circuit；, duty cycle square wave mensuration；, capacitor Frequency conversion.These measurement methods are all made of analog circuit.It is even German
E+H company production intelligent capacitor level meter, and using ac capacitor bridge method carry out capacitor sampling after pass through AD again
Conversion, is then handled with single-chip microcontroller.Its operating mode is substantially: sensing-acquisition-amplification-AD conversion-control operation-DA
Conversion-data output.All there is the distortion of data and drifting problems for these links.
Thus existing technology can not really meet the production requirement of enterprise.
Summary of the invention
Goal of the invention: It is an object of the present invention to solve the deficiency of the existing technology and provide one kind to be based on TDC chip technology
Digitlization capacitive level probe.
Technical solution: in order to achieve the goal above, a kind of digitlization capacitor based on TDC chip technology of the present invention
Formula level meter, comprising: digital sensing unit, micro controller unit, communication or output unit and mechanical structured member, the number pass
Sense unit, micro controller unit and communication or output unit are set in mechanical structured member, wherein the digital sensing unit
Including by capacitance measurement unit, TDC measuring unit, temperature measurement unit, mathematical logic processor, sequence ALU unit, result and
Status register, control and mode register, microprocessor interface unit and compensation circuit are constituted, the capacitance measurement unit
It is made of RLC measuring unit and RLC counter, the RLC measuring unit is connect with TDC measuring unit, the RLC counter
Both ends connect respectively with TDC measuring unit and sequence ALU unit, the TDC measuring unit and temperature measurement unit and data
Logic processor, the temperature measurement unit also with control and mode register connect, the mathematical logic processor also with it is suitable
Sequence ALU unit is connected with result with status register, the result and status register and control and mode register with
The input terminal of microprocessor interface unit connects, the output end and micro controller unit input terminal of the microprocessor interface unit
Connection, the output end of the micro controller unit is connect with the input terminal of communication or output unit, and 8 data are additionally provided in it
Bus, 4 control lines and address latch line.
Capacitance measurement unit of the present invention is by inductance capacitance, reference capacitance, first resistor, analog switch, Switching Power Supply
And control module, the inductance capacitance and reference capacitance connect to form a low-pass filter, the simulation with first resistor
Switch is set between two first resistors, and first resistor, analog switch and the Switching Power Supply is connect with control module, institute
The control module stated by time-to-digit converter, can chronological order device and triode constitute.
TDC measuring unit of the present invention is by numerical register, dynamic itemset counting device, not circuit, Clock dividers, locking phase
Unit and calibration unit are constituted, wherein and Clock dividers, phase locking unit and the calibration unit constitutes data pre-processor,
The numerical register is connected with the equal NAND gate circuit of dynamic itemset counting device, and the NOT gate number in the not circuit determines
Time interval between START signal and STOP signal.
Temperature measurement unit of the present invention is made of resistance, capacitor, high-speed cmos device and temperature sensor, described
In circuit, the both ends of the capacitor are connect with resistance and earthing switch resistor coupled in parallel respectively, and the high-speed cmos device is set to
Between two resistance.
Mechanical structured member of the present invention is made of shell and structural member, and the structural member is set on shell.
A kind of digitlization capacitive level probe and its technological process of production based on TDC chip technology of the present invention,
The specific technological process of production of digitlization capacitive level probe is as follows:
(1): first according to the demand of client, make production notification sheet, including engineering list, technique list, circuit diagram and
Bill of materials；
(2): production division gets required material according to the notification sheet received, and checks the material got；
(3): after material to be confirmed is without lacking, to applied electronic component (such as inductance capacitance, reference capacitance, the first electricity
Resistance, analog switch, Switching Power Supply etc.) it is detected, at the same time, also test to mechanical structured member；
(4): after electronic component and mechanical structured member all confirm that there is no problem, starting electronic component being welded to circuit board
On, and structural member is assembled；
(5): after structural member is completed, start circuit board and structural member to be positioned and controlled assembling, it is so far whole
A digitlization capacitive level probe based on TDC chip technology is completed；
(6): and then to the function and accessory progress in digital sensing unit, micro controller unit, communication or output unit
Test；
(7): after test in upper step after there is no problem, to capacitance measurement unit, TDC measuring unit, temperature measurement unit,
Mathematical logic processor, sequence ALU unit, result and status register, control and mode register, microprocessor interface list
Member, compensation circuit, micro controller unit and communication or output unit are verified respectively；
(8): and then electromagnetic compatibility examination is successively carried out to the digitlization capacitive level probe entirely based on TDC chip technology
It tests, energization degradation, hot test, low-temperature test and comprehensive test；
(9): in each test and checkout procedure in the previous step, once finding any problem, will all be back to
Circuit board and structural member are positioned and are controlled in five steps assembling, to the digitlization capacitance object based on TDC chip technology
Position meter is reprocessed, and after reprocessing, carries out each inspection again；
(10): after in final comprehensive test confirmation, there is no problem, which being packed；
(11): shipment finally being carried out to packaged product.
The utility model has the advantages that the digitlization capacitive level probe of the present invention based on TDC chip technology, has following excellent
Point:
1, a kind of digitlization capacitive level probe based on TDC chip technology of the present invention, it is single by measuring TDC
Member is connect with mathematical logic processor, by digitlization TDC application signal by the delay time of interior logic gate come high-precision
Time of measuring interval keeps chip point-device again by simple circuit structure and special circuit board wiring method
Construction signal is by logic gate number, and full accuracy depends on the largest logical gate delay time of chip, using such basis
Measuring unit and the CMOS technology of modernization, which combine, can make time resolution reach 25 picoseconds, to make capacitance measurement point
Resolution reaches 6af.Method resolution ratio than traditional analog circuit measurement capacitor improves 1000 orders of magnitude or more, anti-interference
Ability improves 10 times or more, thus the problem of very good solution anti-intense radiation interference.
2, the setting of heretofore described capacitance measurement unit, temperature measurement unit and compensation circuit, so that the level
Collected simultaneously and analysis parameter has the conductivity and temperature of capacitance change, medium in meter, these parameters are through overcompensation electricity
Power carries out comprehensive analysis of system compensation, to obtain accurate level value, the application of multi-parameter integrated compensation technique makes condenser type
Level meter thoroughly solves the problems, such as bridging and temperature drift problem.
3, the data sensor and acquisition in the heretofore described digitlization capacitive level probe based on TDC chip technology
Digital technology is used entirely, and the transmission of data uses serial communication, gauge internal links do not have analog quantity ingredient, are not present
AD conversion, thus ensure that the authenticity of data to the full extent, so that very good solution is in sensing-acquisition-amplification-
Data distortion and drifting problem caused by AD conversion-control operation-DA conversion-data output whole process, so it is more preferable
The needs for meeting client.
Detailed description of the invention
Fig. 1 is the principle of the present invention structural schematic diagram；
Fig. 2 is the circuit connection diagram of capacitance measurement unit of the present invention；
Fig. 3 is the circuit connection diagram of heretofore described TDC measuring unit；
Fig. 4 is the circuit connection diagram of heretofore described temperature measurement unit；
In figure: digital sensing unit -1, micro controller unit -2, communication or output unit -3, capacitance measurement unit -4,
TDC measuring unit -5, temperature measurement unit -6, mathematical logic processor -7, sequence ALU unit -8, result and status register -
9, control and mode register -10, microprocessor interface unit -11, RLC measuring unit -41, RLC counter -42, induced electricity
Hold -43, reference capacitance -44, first resistor -45, analog switch -46, Switching Power Supply -47, control module -48, numerical register -
51, dynamic itemset counting device -52, not circuit -53, Clock dividers -54, phase locking unit -55, data pre-processor -56.
Specific embodiment
In the following with reference to the drawings and specific embodiments, the present invention is furture elucidated.
Embodiment
A kind of digitlization capacitive level probe based on TDC chip technology as shown in Figure 1, Figure 2, Figure 3 and Figure 4, comprising:
Digital sensing unit 1, micro controller unit 2, communication or output unit 3 and mechanical structured member, wherein the digital sensing list
Member 1 includes by capacitance measurement unit 4, TDC measuring unit 5, temperature measurement unit 6, mathematical logic processor 7, sequence ALU unit
8, result and status register 9, control and mode register 10, microprocessor interface unit 11 and compensation circuit are constituted, described
Capacitance measurement unit 4 be made of RLC measuring unit 41 and RLC counter 42, the mechanical structured member is by shell and structure
Part is constituted.
The relationship of above-mentioned each component is as follows:
The digital sensing unit 1, micro controller unit 2 and communication or output unit 3 are set in mechanical structured member, institute
The structural member stated is set on shell, and the RLC measuring unit 41 is connect with TDC measuring unit 5, the RLC counter 42
Both ends are connect with TDC measuring unit 5 and sequence ALU unit 8 respectively, the TDC measuring unit 5 and 6 sum number of temperature measurement unit
According to logic processor 7, the temperature measurement unit 6 is also connect with control and mode register 10, the mathematical logic processor 7
It is also connect with sequence ALU unit 8 and result and status register 9, the result and status register 9 and control are posted with mode
Storage 10 is connect with the input terminal of microprocessor interface unit 11, the output end and micro-control of the microprocessor interface unit 11
2 input terminal of device unit connection processed, the output end of the micro controller unit 2 are connect with the input terminal of communication or output unit 3, and
8 bit data bus, 4 control lines and address latch line are additionally provided in it.
Capacitance measurement unit 4 described in the present embodiment is opened by inductance capacitance 43, reference capacitance 44, first resistor 45, simulation
It closes 46, Switching Power Supply 47 and control module 48, the inductance capacitance 43 and reference capacitance 44 connect formation with first resistor 45
One low-pass filter, the analog switch 46 are set between two first resistors 45, and the first resistor 45, analog switch
46 and Switching Power Supply 47 connect with control module 48, the control module 48 by time-to-digit converter, can chronological order fill
It sets and is constituted with triode.
TDC measuring unit described in the present embodiment 5 is by numerical register 51, dynamic itemset counting device 52, not circuit 53, clock
Frequency divider 54, phase locking unit 55 and calibration unit are constituted, wherein Clock dividers 54, phase locking unit 55 and the calibration list
Member constitutes data pre-processor 56, the numerical register 51 and the connection of the equal NAND gate circuit 53 of dynamic itemset counting device 52, and institute
It states the NOT gate number in not circuit 53 and determines time interval between START signal and STOP signal.
Temperature measurement unit 6 described in the present embodiment is by resistance, capacitor, high-speed cmos device and temperature sensor structure
At in circuit, the both ends of the capacitor are connect with resistance and earthing switch the resistor coupled in parallel respectively, the high-speed cmos device
Part is set between two resistance.
It provides high-precision and low offset and very low gain drift to compensation circuit described in the present embodiment, described
Inductance capacitance 43, reference capacitance 44 are all grounded, they are obtained respectively passes through a capacitor electric discharge by an analogue selector selection.Mould
Quasi- selector is by PS21 chip controls, and only 2 capacitors can be compared to each other；In addition C-A1 port tube foot is made again
With can be connected to ground.Additional special circuit and mathematical algorithm compensate internal parasitic capacitances in the chip, this
Parasitic capacitance not only includes the parasitic capacitance on chip while including all component stray capacitances in analog switching circuit
Compensation, the integrated measurement accuracy of capacitive level probe reaches one thousandth or more after comprehensive compensation, to better meet
The demand of user.
A kind of digitlization capacitive level probe and its technological process of production based on TDC chip technology in the present embodiment, should
It is as follows to digitize the specific technological process of production of capacitive level probe:
(1): first according to the demand of client, make production notification sheet, including engineering list, technique list, circuit diagram and
Bill of materials；
(2): production division gets required material according to the notification sheet received, and checks the material got；
(3): after material to be confirmed is without lacking, to applied electronic component (such as inductance capacitance 43, reference capacitance 44,
One resistance 45, analog switch 46, Switching Power Supply 47 etc.) it is detected, at the same time, also test to mechanical structured member；
(4): after electronic component and mechanical structured member all confirm that there is no problem, starting electronic component being welded to circuit board
On, and structural member is assembled；
(5): after structural member is completed, start circuit board and structural member to be positioned and controlled assembling, it is so far whole
A digitlization capacitive level probe based on TDC chip technology is completed；
(6): then to digital sensing unit 1, micro controller unit 2, communication or output unit 3 in function and accessory into
Row test；
(7): after after test in upper step, there is no problem, capacitance measurement unit 4, TDC measuring unit 5, temperature being measured single
Member 6, mathematical logic processor 7, sequence ALU unit 8, result and status register 9, control and mode register 10, micro process
Device interface unit 11, compensation circuit, micro controller unit 2 and communication or output unit 3 are verified respectively；
(8): and then electromagnetic compatibility examination is successively carried out to the digitlization capacitive level probe entirely based on TDC chip technology
It tests, energization degradation, hot test, low-temperature test and comprehensive test；
(9): in each test and checkout procedure in the previous step, once finding any problem, will all be back to
Circuit board and structural member are positioned and are controlled in five steps assembling, to the digitlization capacitance object based on TDC chip technology
Position meter is reprocessed, and after reprocessing, carries out each inspection again；
(10): after in final comprehensive test confirmation, there is no problem, which being packed；
(11): shipment finally being carried out to packaged product.
Examples are only for illustrating the present invention and not for limiting the scope of the present invention, after the present invention has been read, this
Field technical staff falls within the application range as defined in the appended claims to the modification of various equivalent forms of the invention.
Claims (6)
1. a kind of digitlization capacitive level probe based on TDC chip technology, it is characterised in that: include: digital sensing unit
(1), micro controller unit (2), communication or output unit (3) and mechanical structured member, the digital sensing unit (1), microcontroller
Device unit (2) and communication or output unit (3) are set in mechanical structured member, wherein the digital sensing unit (1) includes
It is mono- by capacitance measurement unit (4), TDC measuring unit (5), temperature measurement unit (6), mathematical logic processor (7), sequence ALU
First (8), result and status register (9), control and mode register (10), microprocessor interface unit (11) and compensation circuit
It constitutes, the capacitance measurement unit (4) is made of RLC measuring unit (41) and RLC counter (42), the RLC measurement
Unit (41) is connect with TDC measuring unit (5), the both ends of the RLC counter (42) respectively with TDC measuring unit (5) and suitable
Sequence ALU unit (8) connection, the TDC measuring unit (5) and temperature measurement unit (6) and data logic processor (7), it is described
Temperature measurement unit (6) also with control and mode register (10) connect, the mathematical logic processor (7) also with sequence ALU
Unit (8) and result and status register (9) connection, the result and status register (9) and control and mode register
(10) connect with the input terminal of microprocessor interface unit (11), the output end of the microprocessor interface unit (11) with it is micro-
The connection of controller unit (2) input terminal, the output end of the micro controller unit (2) and communication or the input of output unit (3)
End connection, and 8 bit data bus, 4 control lines and address latch line are additionally provided in it.
2. a kind of digitlization capacitive level probe based on TDC chip technology according to claim 1, it is characterised in that:
The capacitance measurement unit (4) is by inductance capacitance (43), reference capacitance (44), first resistor (45), analog switch (46), switch
Power supply (47) and control module (48), the inductance capacitance (43) and reference capacitance (44) connect formation with first resistor (45)
One low-pass filter, the analog switch (46) are set between two first resistors (45), and the first resistor (45), mould
Quasi- switch (46) and Switching Power Supply (47) are connect with control module (48), and the control module (48) is by time-to-digital converter
Device, can chronological order device and triode constitute.
3. a kind of digitlization capacitive level probe based on TDC chip technology according to claim 1, it is characterised in that:
The TDC measuring unit (5) is by numerical register (51), dynamic itemset counting device (52), not circuit (53), Clock dividers
(54), phase locking unit (55) and calibration unit are constituted, wherein Clock dividers (54), phase locking unit (55) and the calibration
Unit constitutes data in processor (56), the numerical register (51) and dynamic itemset counting device (52) NAND gate circuit (53)
Connection, and the NOT gate number in the not circuit (53) determines the time interval between START signal and STOP signal.
4. a kind of digitlization capacitive level probe based on TDC chip technology according to claim 1, it is characterised in that:
The temperature measurement unit (6) is made of resistance, capacitor, high-speed cmos device and temperature sensor, the resistor coupled in parallel in
In circuit, the both ends of the capacitor are connect with resistance and earthing switch respectively, and the high-speed cmos device is set between two resistance.
5. a kind of digitlization capacitive level probe based on TDC chip technology according to claim 1, it is characterised in that:
The mechanical structured member is made of shell and structural member, and the structural member is set on shell.
6. a kind of digitlization capacitive level probe and its technological process of production based on TDC chip technology, it is characterised in that: the number
The specific technological process of production of word capacitive level probe is as follows:
(1): first according to the demand of client, production notification sheet is made, including engineering list, technique list, circuit diagram and material
It is single；
(2): production division gets required material according to the notification sheet received, and checks the material got；
(3): after material to be confirmed is without lacking, to applied electronic component, such as: inductance capacitance (43), reference capacitance (44),
One resistance (45), analog switch (46) and Switching Power Supply (47) are detected, and at the same time, are also examined to mechanical structured member
It tests；
(4): after electronic component and mechanical structured member all confirm that there is no problem, start for electronic component to be welded on circuit board,
And structural member is assembled；
(5): after structural member is completed, starting circuit board and structural member to be positioned and controlled assembling, so far entire base
It is completed in the digitlization capacitive level probe of TDC chip technology；
(6): and then to the function and accessory in digital sensing unit (1), micro controller unit (2), communication or output unit (3)
It is tested；
(7): after after test in upper step, there is no problem, capacitance measurement unit (4), TDC measuring unit (5), temperature being measured single
First (6), mathematical logic processor (7), sequence ALU unit (8), result and status register (9), control and mode register
(10), microprocessor interface unit (11), compensation circuit, micro controller unit (2) and communication or output unit (3) are distinguished
Verification；
(8): and then EMC test is successively carried out to the digitlization capacitive level probe entirely based on TDC chip technology, lead to
Electrical ageing test, hot test, low-temperature test and comprehensive test；
(9): in each test and checkout procedure in the previous step, once finding any problem, will all be back to the 5th step
In circuit board and structural member are positioned and are controlled assembling, to the digitlization capacitive level probe based on TDC chip technology
It is reprocessed, and after reprocessing, carries out each inspection again；
(10): after in final comprehensive test confirmation, there is no problem, product being packed；
(11): shipment finally being carried out to packaged product.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510407579.8A CN105181080B (en) | 2015-07-13 | 2015-07-13 | A kind of digitlization capacitive level probe based on TDC chip technology |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510407579.8A CN105181080B (en) | 2015-07-13 | 2015-07-13 | A kind of digitlization capacitive level probe based on TDC chip technology |
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| CN105181080A CN105181080A (en) | 2015-12-23 |
| CN105181080B true CN105181080B (en) | 2019-03-19 |
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| CN110879092B (en) * | 2019-11-29 | 2020-12-01 | 安徽江淮汽车集团股份有限公司 | Liquid level monitoring circuit |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2121020U (en) * | 1992-04-17 | 1992-11-04 | 卢亮 | Digit capacitance level-sensing device |
| CN2289221Y (en) * | 1997-04-14 | 1998-08-26 | 郭金运 | Capacitive continuous detecting bin level indicator |
| CN201974212U (en) * | 2010-12-08 | 2011-09-14 | 上海自动化仪表股份有限公司 | Capacitive radio frequency admittance level transmitter |
| CN204902951U (en) * | 2015-07-13 | 2015-12-23 | 淮安伟岸自控设备有限公司 | Digital capacitanc level meter based on TDC chip technology |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7150190B2 (en) * | 2005-03-21 | 2006-12-19 | Dade Behring Inc. | Method and apparatus for capacitively determining the uppermost level of a liquid in a container |
-
2015
- 2015-07-13 CN CN201510407579.8A patent/CN105181080B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2121020U (en) * | 1992-04-17 | 1992-11-04 | 卢亮 | Digit capacitance level-sensing device |
| CN2289221Y (en) * | 1997-04-14 | 1998-08-26 | 郭金运 | Capacitive continuous detecting bin level indicator |
| CN201974212U (en) * | 2010-12-08 | 2011-09-14 | 上海自动化仪表股份有限公司 | Capacitive radio frequency admittance level transmitter |
| CN204902951U (en) * | 2015-07-13 | 2015-12-23 | 淮安伟岸自控设备有限公司 | Digital capacitanc level meter based on TDC chip technology |
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Effective date of registration: 20190506 Address after: 223001 No. 88 Huancheng West Road, Jinhu County Industrial Park, Huaian City, Jiangsu Province Patentee after: Jiangsu Jack Instrument Co., Ltd. Address before: 211600 Jinhu County Industrial Park, Huaian City, Jiangsu Province, No. 88-1, Huancheng West Road Patentee before: HUAI'AN WEIAN AUTOMATIC CONTROL EQUIPMENT CO., LTD. |